The urgent need to mitigate the environmental impacts of fossil fuel combustion has spurred interest in renewable energy sources for electricity generation, particularly solar organic Rankine cycles (ORCs). This study investigates the potential of fluid mixtures in low-temperature ORCs, focusing on a radial turbine. While fluid mixtures have shown promise for heat recovery in low-temperature applications, previous research often overlooked turbine characteristics by assuming constant efficiencies. This study set out to examine the impact of turbine characteristics on the ORC performance when adapting fluid mixtures by coupling a cycle-turbine model incorporated with real gas analysis. The outcomes of the turbine model are exported to the cycle model to evaluate its performance. Results reveal significant variations in cycle performance due to turbine power and efficiency, outweighing the effects of temperature glide in fluid mixtures. Although fluid mixtures enhance thermal compatibility with heat sources, certain pure fluids exhibit superior cycle performance owing to better turbine characteristics. Moreover, the assumption of constant turbine efficiency compromises result accuracy by up to 45 % compared to dynamic turbine efficiency. Notably, the isobutane/isopentane mixture (0.7/0.3) emerges as the most favourable, achieving a turbine power of 48.90 kW, turbine efficiency of 71 %, and thermal efficiency of 12.29 %.

中文翻译：

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涡轮机特性对使用非共沸和共沸混合物运行的低温有机朗肯循环的影响

减轻化石燃料燃烧对环境影响的迫切需要激发了人们对可再生能源发电的兴趣，特别是太阳能有机朗肯循环（ORC）。本研究研究了低温 ORC 中流体混合物的潜力，重点关注径流式涡轮机。虽然流体混合物在低温应用中显示出热回收的前景，但之前的研究经常通过假设恒定的效率而忽略了涡轮机的特性。本研究旨在通过将循环涡轮机模型与实际气体分析结合起来，研究在调整流体混合物时涡轮机特性对 ORC 性能的影响。涡轮机模型的结果被导出到循环模型以评估其性能。结果表明，涡轮机功率和效率导致循环性能发生显着变化，超过了流体混合物中温度滑移的影响。尽管流体混合物增强了与热源的热相容性，但某些纯流体由于更好的涡轮机特性而表现出优异的循环性能。此外，与动态涡轮机效率相比，恒定涡轮机效率的假设会使结果精度降低高达 45%。值得注意的是，异丁烷/异戊烷混合物 (0.7/0.3) 最为有利，涡轮机功率为 48.90 kW，涡轮机效率为 71%，热效率为 12.29%。